Jadis JA 200 monoblock power amplifier Dick Olsher's System

Sidebar 1: Dick Olsher's System

Over the course of several months I was able to test the Jadises with a variety of loudspeakers, particularly the MartinLogan Quest Z, the Nestorovic Type 5AS Signature, and the Mach 1 Acoustics DM-10 Signature. I change speaker cables as often as most people change socks—though I keep returning to TARA Labs RSC.

The front-end featured the Jadis JP 80MC full-function preamp, the Air Tight ATC-2 line-level preamp, the Theta DS Pre digital processor (with signal obtained from Tape Out), and the Basis Ovation turntable outfitted with the Graham Model 1.5t arm and the Lyra Clavis and Audio-Technica ART-1 cartridges.—Dick Olsher

US distributor: Bluebird Music Ltd.
275 Woodward Avenue
Buffalo, NY 14217
(416) 638-8207

mrkaic's picture

"I've never been a fan of the 6550A, which is really not an audio tube at all."

How is the audio vs. no audio tube supposed to matter? Correct me if I'm wrong, but what matters for amplifier design are the characteristics of the tube, e.g. plate current vs plate voltage etc.

Incidentally, I remember reading a rather disappointing review of a Jadis amplifier on this website. (https://www.stereophile.com/content/jadis-se300b-monoblock-amplifier-measurements) Why no measurements here?

supamark's picture

This review is like 25 years old, and if you really want an answer to your question about why Mr. Olsher doesn't like certain tubes you can find him at The Absolute Sound, a rival magazine that prides itself on reviews based only on listening - they don't need, or want, your stinkin' measurements. They'll loooove you over there...

NB - I like measurements.

mrkaic's picture

Thank you for the information. I will try to contact Mr. Olsher. I'm hope he will be glad to explain his views.

John Atkinson's picture
mrkaic wrote:
Why no measurements here?

Our image archive only goes back as far as October 1995, when we started producing Stereophile using DTP. (DeskTop Publishing). The Audio Precision test files for the JA 200 weren't in my archive for some reason, so I had to look for the original workbook. Unfortunately, when I found it, it turned out TJN had saved the files on a 5¼" floppy disk and I no longer have a drive for that format.

I didn't want to hold up posting the review to the website, so we did so before I could scan the original printouts of the graphs and formatted the image files. I have now added the measurement sidebar with all of its graphs.

John Atkinson
Editor, Stereophile

mrkaic's picture

You make a super valid point -- some important information might get lost because we no longer have drives to read old magnetic media. I ditched my old floppy drives a few years ago and maybe it was not such a good idea.



tonykaz's picture

I've only ever had one Tube Amp that I could love, it had EL34s.

I've sold the entire 1985 line of Conrad-Johnson Amps that had 6550 output tubes, these Amps were OK but not beautiful like the little EL34 based MV-45a.

Mr.JVS in Port Townsend is about to report on these Jadis Amps. , I'll bet that he can't love em enough to own em.

Tubes run great until one day when they don't, a good SS Amp runs great for decades.

Tony in Michigan

ps. 6SN7 pre-amp tubes are the way to go

Charles Hansen's picture

While the Jadis preamplifiers had very "standard" circuit topologies, their power amps (at least of that era) were different than anything else I had ever seen before. Specifically, they used *positive* feedback to increase the overall gain of the circuit.

(This same techniques was used in many old radio receivers of the '20 and '30s, where it was called a "super-regenerative" design that was almost completely supplanted by the later and superior "heterodyne" design - which was called "super-heterodyne" for purely marketing reasons! One did not want to go backwards from a "super" circuit to an "ordinary" circuit, regardless of which was actually better - ain't marketers slick, even back before WW2? We have Edward Bernays to thank for much of insanity of today's modern society.)

In the Jadis audio power amplifiers, the positive feedback increased the gain for a different reason - so that they could use more *negative* feedback without adding another gain stage or reducing the overall gain. A bizarrely interesting and uniquely French way of doing things differently. These twin feedback colorations were responsible not only for the Jadis's unique sound, but also helps explains its extraordinary sensitivity to AC power line conditions (including line conditioners and power cords).

Bit of obscure audio history for you there, and a large tip of the hat to Ken Stevens of CAT for explaining it so clearly to me. Enjoy!

EDIT: Apologies for the "history lesson" error. There never was a "super regenerative" radio receiver - only a "regenerative" one. The term "super heterodyne" was coined by its inventor, Edwin Armstrong (later to invent frequency modulation, or FM). The "super" part was short for "supersonic" (he actually meant ultrasonic, as supersonic means faster than the speed of sound). "Hetero" means mixed, and "dyne" is from the Greek word for "power" (dynamo, dynamic, dynasty - even "dynamite").

tonykaz's picture

Thanks for the explanation.

Now, can you help explain the Jadis Price Structure? if there is one.

Any typical Retail item will have a 20% of Retail Sale price as Cost to Manufacture ( Proctor & Gamble are at about 9% ).

Importing adds another layer of Costs.

These Jadis things look rather Industrial, almost like something we'd find in a Sears Silverstone Stereo Console.

What is so darn compelling about these Amps?

Tony in Michigan

Charles Hansen's picture

I'm not sure there was much different about Jadis than any other imported audio product. As you note, shipping and an extra layer of profit for the importer adds to the cost of almost all imported products. The hadis amplifiers were expensive to build because of three major things - their massive transformers (both power and output, which were far larger than found on competing products), their meticulous point-to-point hand wiring done by French (not Chinese slave labor), and finally the polished chrome-plated steel chassis - also requiring a lot of hand labor.

For those with an eye for those details, they are as impressive (if not more so) than a 1" thick front panel. It's mostly just cultural differences that have us pay attention to certain details and notice the value therein, I believe. Victor Goldstein may have had a slightly higher distributor margin than typical, but not by much. He was based in New York and had to have a full-time technician of Chinese descent to repair and maintain them. (They had a lot of reliability issues!) I've forgotten his name, but after Mr. Goldstein stopped importing Jadis, his former technician (Da Hong? Ming Da? or something similar) used to both modify Jadis amps and also build his own amps from scratch. You will see the technician's name mentioned in the old TAS digest-sized issues when HP would review the Jadis amps.

The compelling thing was their sound. I think the JA-80 (single pair of output tubes) was more successful, and I heard some absolutely amazing sound from those amps. Hope that helps.

tonykaz's picture

Ayre takes "Digital Product of the Year"


Tony in Michigan

ps. thanks for your exotic amp comments. I've sold Tube gear and kinda agree with y'all on these things being what I call twitchy and prone to blowing up. phew ( keep u'r fingers crossed )

Having said that, my 1960 era Mac Tube Mono amp never blew itself up, nor did any of the Audible Illusions I sold ( thank god ).

I've heard horror stories about big Tube Amps.

I sold Electrocompaniet and didn't at-all miss the 'variables' of having to cope with tube gear.

I was once importing Tim De Paravicini's various tube Amps and didn't have a blow-up problem but they were waaaaaaaay over rated and didn't sound all that wonderful compared to a conrad-johnson Mv-75a. The Mv-45a was a sweet-hearted little charmer that I wish I still owned one of.

That gorgeous and charismatic sound quality you refer to is a rare bird. I had a local technician that would modify any used tube pre-amp he could get his hands on, his modified stuff would blow the doors 'Off' any of our Retail Showroom Products. His secrets were; especially fine resistors, expensive/exotic Caps. and Russian Tubes. His stuff typically had a short half-life.